Self-loading and unloading vehicle



Oct. 14, 1952 H. J. VAN DOORNE 2,613,827

SELF-LOADING AND UNLOADING VEHICLE Filed Aug. 25. 1948 I 5 Sheets-Sheet 1 FIGJ N INVENTOR.

HUBERTMS' JOSEPHUS V4N DOORNE Oct: 14, 1952 H. J; VAN DEJQRNE SELF-LOADING AND UNLOADING VEHICLE Filed Aug. 23. l9 48 Oct. 14, 1952 H. J. VANIDIO0RNE SELF-LOADING ANDHUNLOADING VEHICLE 5 Sheets-Sheet 3 Filed Aug. 23. 1948 INVENTOR. HUBERTUS JOSEPHUS l/4N DOORNE H. J. VAN DOORNE -LOADING AND UNLOADING VEHICLE SELF Oct. 14, 1952 5 Sheets-Sheet 4 Filed Aug. 23. 1948 INVENTOR.

M R m N W w W w m R w Oct. 14, 1952 H. J. VAN doRNE SELF-LOADING AND UNLOADING VEHICLE 5 Sheets-Sheet 5 Filed Aug. 23. 1948 998 N8, 1| w mmw m gum-U 1 who: 1

INVENTOR. HUBERTUS VOSEPHUS l/4N DOOR/V5 Patented Oct. 14, 1952 SELF-LOADING AND UNLOADING VEHICLE Hubertus Josephus van Doorne, Deurne', Netherlands Application August 23, 1948, Serial No. 45,642

In Belgium September 6,1947

16 Claims.

This invention relates to a self-loading and unloading vehicle. More particularly, it deals with the control mechanism for such a vehicle. For

example in a vehicle for handling special containers such as LCL (less than carload lot) containers between a railway station or railway car and the place where the container is filled or emptied, this invention deals with the mechanism for moving the container onto and off of the vehicle from a railway car, the ground, or a plat-.

form; the control of such mechanism; and the locking of the container and the mechanism when, the container is in its position to be trans-- ported on the vehicle.

It is an object of this invention to provide a new, eflicient, effective self-loading and unloading vehicle with a simple, positive, non-jamming, fool-proof control and locking mechanism for the self-loading and unloading equipment on the vehicle.

Another object is to provide improvements over Dutch Patents No. 50,510 and No. 55,777.

In accordance with this invention, the vehicle for transporting a container comprises: a main frame, an auxiliary frame mounted on said main frame to support said container, means to move said container onto and off of said auxiliary frame, means to tilt said auxiliary frame for! wardly and backwardly, and means to lock said moving means and said tilting means when said auxiliary frame is in its container carrying position.

In one embodiment of this invention, separate axes are provided at each end of the auxiliary frame which may be both or alternativelyengaged to lock or to tilt, respectively, the auxiliary frame forwardly or backwardly about either axis. Two separate manual control devices may be provided, one or the first of which alternately locks either one or both of the tiltingv axes to the main frame and co-operates with the other or second control device, which other device controls the actual tilting of the auxiliary frame and may also control a pushing and pulling mechanism for moving the container onto or off of the auxiliary frame. This other or second control device is preventedfrom operating when both axes of the auxiliary frame are locked to the main frame, so that the tilting mechanism for the auxiliary frame as well as the pushing'and pulling mechanism cannot then be operated; and. correspondingly when the first control device is in a given operating position it cannot be changed into another operatingposition as long as the second control device is in one of its operating positions.

This co-operation between the two control devices prevents jamming of r the mechanism and prevents any operator from making an error in their operation which might unexpectedly discharge and/or damage the container. Furthermore, special universally adjustable clamping devices may be provided on thejauxiliary frame for fastening thecontainer intoits .carryingposition. The auxiliary frame tilting mechanism and the pushing and pulling mechanism may comprise fluid pressure or vacuum reciprocating motors, hydraulic pistons, gears and racks or the like, and the second control device may comprise a valve or switchmeans to control the flow of the fluid or energy for said motors, gears, or racks. I

The above mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is a side elevation of a part of a tractor with a'semi-trailer showing one embodiment of this invention with the auxiliary frame in its container carrying or transporting position; v Fig. 2 is similar to Fig. 1 with a container carried on the auxiliary frame and with the auxiliary frame tilted forwardly for the transfer of the container to or from a railway car or other plat- 1 form higher than the carrying position of the auxiliary frame;

Fig. 3 is similar to Fig. .2 with the auxiliary frame tilted rearwardly in order to transfer the container to or from the ground;

Fig. 4 is similar to Fig. 2 showing the auxiliary frame tilted rearwardly at a sufficiently high angle so that the contents of a container mounted thereon may be dumped or its contents removed without removing the container from the auxiliary frame;

Fig. 5 is a plan view of the part of'the tractor and of the semi-trailer shown in Fig. 1;

Fig. 6 is a detailed side elevation of the main frame with the auxiliary frame tilted forwardly;

Fig. '7 is similar to Fig. 6 with the auxiliary frame tilted rearwardly; 1

Fig. 8 is a detailed sideview of one of the locking means mounted on the auxiliary frame for holding the container in its carrying position, partly shown in vertical section; v

Fig. 9 is a schematic perspective View of a mechanical device or system for selectively loch- ,ing the forward, the backward and both tilting frame 30.

motions of the auxiliary frame and its co-operation with a hydraulic device or system for selectively operating the tilting means of the auxiliary frame and the moving means of the container.

Fig. is a schematic diagram of the hydraulic system of Fig. 9 showing the passages for fluid through the pump and the manual control valve on to the hydraulic motor means;

Figs. 11, 12, 13 and 14 are schematic sections of the control valve core member shown in Fig. 10 in its four different adjustable positions;

Fig. 15 is a detailed view of one of the locking hooks for the tilting axes showing in dot and dash lines the different operating positions thereof;

Fig. 16 is a detail front View of one embodiment of' the manual control handles of the control valve in Fig. 10, with parts broken away; and

Fig. 17 is a view similar to Fig. 16, with the control handles and dial removed to show the co-operation of the mechanical and the hydraulic control devices or systems.

Referring to Fig. 1 there is shown the rear :part of a. tractor 20 and the semi-trailer 2| the front end of which rests on the fifth wheel 22 of the tractor 20.

The trailer 2| comprises a main frame 23 mounted on two pairs of rear wheels 24, each of which pairs may be adapted to swivel about a longitudinal axle 25. The front end of the trailer may have a support 26 resting on the fifth wheel22, and may. also have retractable supporting wheels 21, shown in Figs. 2, 3 and 4 but not in Fig. 1 for the sake of clearness, which wheels 21 may be provided with a steering rod 28, shown in its inoperative position in Figs. 2, 3 and 4. On the front ends of the swivel axles may be mounted brake cylinders or diaphragms 29. On top of the main frame 23 is mounted a tiltable auxiliary frame 3|] which supports a special container, such as 3| (shown in Figs. 2 and 3) or 32 (shown in Fig. 4).

The containers 3| and 32 are provided with equal axially spaced rollers 33 which roll along the parallel channels or tracks 35 of the auxiliary The auxiliary frame 30 may be supported along either one or both of two parallel axes comprising trunnions and 4| mounted on the main frame 23 which engage the semibearings 42 and 43 (see Figs. 6 and 7 near opposite ends A tilting mechanism for the auxiliary frame 30 may be mounted beof the auxiliary frame 30.

tween the axes of trunnions 40 and 4|, which as shown herein comprises a telescopic hydraulic jack 45 pivotally mounted to the main frame 23 at 46. V v

A pushing and pulling mechanism or transfer device may be pivotally mounted on the main frame and connected to the auxiliary frame 30 so that it may be tilted with the auxiliary frame in. the rearwardly direction as shown in Figs. 3

and 4. This transfer device may comprise another hydraulic cylinder such as that shown in Van Doorne Dutch Patent 55,777 and shown schematically in the upper right portion of Fig. 10, and a connecting rod 52 for connecting it to container 3| or 32 so that these containers may be'pushed or pulled onto or off of the tracks 35 of the auxiliary frame 30. When the container 3| or 32 is in its transporting position it may be 'fastened in that position by means of hooks and adjustable universal hooks 6| (shown in detail in Fig. 8).

In this position shown in Fig. 1, the manual control device 10 for selectively fastening the tiltable auxiliary frame 30 to either one or both of the axes 40 or 4| is shown in its middle position wherein both the axes are hooked as shown in the full line position of the hook. (I shown in Fig. 15.

If the auxiliary frame 3|].is to be tilted forwardly about the forward axis of trunnions 40 as shown in Figs. 2,and 6, the manual control device or lever 10 is pulled forward so that the forward hooks 1| closely engage the trunnions 40 on each side of the main frame 23, as shown in position 12 in Fig. 15. This motion through link connections 73 and 14 (see Figs. 1, 5, 6, 7 and 9) simultaneously disengages the hooks 75 (corresponding to 1|) from the trunnions 4| so that when the second manual control device is operated to extend the piston 45, the auxiliary frame 3|] will be tilted forwardly around the axis of trunnions 40 as shown in Figs. 2 and 6. The advantage of tilting the auxiliary frame 30 in this direction enables the vehicle to unload containers 3| from levels higher than that of the normal carrying position of the auxiliary frame shown in Fig. 1, such as from the floor of a railway car 28 as shown in Fig. 2, or the floor of a railway depot plateform of substantially the same height. In order to form a bridge when pushing or pulling the container, telescoping extensions 36 may be provided for each track 35 to engage the nearest edge of the platform or railroad car as shown in Fig. 2. The relative dimensions of the container with respect to that of an ordinary railway car would permit several such containers to be placed on one car, and hence the name of LCL for such containers.

When the lever 10 is pushed rearwardly as shown in Figs. 3, 4, 7 and 9, the hooks 75 fully engage the rear trunnions 4| through the link connections 13 and 14, and simultaneously hooks disengage the lower edge of the trunnions 40, as shown in the dotted line position 16 in Fig. 15. Now when the second control device 80 is operated to extend the hydraulic mechanism 45, the auxiliary frame 30 is tilted rearwardly as shown in Figs. 3 and 4. If a container such as 3| or 32 is to be transferred to or from the ground level the extensions 36 of the rails 35 may be extended to touch the ground as shown in Fig. 3, so that the container may be easily pulled or pushed onto or off of the frame 30 solely by means of the transferring device 50.

Similarly, if a container such as 32 with a rearwardly opening end 31 is transported on the vehicle, the vehicle may act as a dump truck and dump the contents of the container directly as shown in the position of Fig. 4, by extending the mechanism 45 a greater distance than that shown in Figs. 3 and 7.

The second manual control device shown in detail in Figs. 9 to 14, 16 and 17, may comprise a lever with opposing handles 8| to which is attached the pointer 82, so that the control valve 88 (see Figs. 10-14) for the hydraulic mechanisms 45 and 50 may be selectively adjusted into any one of four positions, as follows; N, the neutral position in which no fluid pressure is applied to the cylinders of either of the devices 45 and 50 and the pump is connected to a fluid reservoir (see Fig. 10 or 11); A, the position in which the transfer mechanism 50 operates to push the container from the vehicle (see Fig. 12) B, the position in which the transfer mechanism 50 operates to pull the container onto the vehicle (see Fig. 13); and C, the position in which the fluid pressure is supplied to the hydraulic tilting mechanism 45 to tilt the auxiliary frame 30 (see tioning the control valve 88.

85 and its cam'surface 86 from cam 81.

Fig. 14) After the lever 8| places the pointer v into the position desired, a separate manual valve with handle 83 may be operated to regulate the amount of pressure and fluid to be admitted to the mechanism-45 or 58. I

In connection with the operation of handle 8i, there is provided a safety device more clearly shown in Figs-9 and l'l, which is operated with the motion of the first control'handle 18 through the link 84- and cam lever 85 to engage or disengage its cam'surface 86 with the cam 81 mounted to turn'with the'handle 8| for posi- When the handle 8| is in'its neutral position as shown in Figs. 16 and 17, and the axlelocking device I8 is in its middle position as shown in Fig. l, the control device 88 cannot be operated or turned until the lever 18 is placed in either'its forward or backward position. Thus, when the tiltable platform is connected at both'ends by hooks H and T5 to 'is againplaced in its neutral position. However,

oncethe lever 18 is operated to lock the first controldevicein either its forwardly or rearwardly tilting. position, the control valve 88 may be set by handle 8! into anyone of its four positions N, A, B,'or'C, (see Fig. 16) by the operation on handleSl, to provide for the proper tilting of the auxiliary frame 38 (inposition C) and the extension and retraction of the transfer mechanism 58 (in positions .A and B respectively), and thenthe replacement of the auxiliary frame into its container carrying position: (in position N).

The transfer mechanism 58 as disclosed in Van Doorne Dutch Patent No. 55,777 comprises a double active hydraulic cylinder .28] (see Fig.

2 II is heldstationarytby its connection '2l2,"the upper run and member 2l3 with rod 52 will be displaced over a distance twiceas long as the displacement of cylinder 28], thereby multiplying the motion of the cylinder 281. 5

The hydraulic system schematically represented in Figs. 9 and 10 comprises a hydraulic pump 228 of any known suitable type connected with its suction side through a duct 22! to a fluid tank or reservoir 222, and with its pressure side through a duct 223 to the housing 224 of the above mentioned control valve 88. A bypass duct 225 connects duct 223 through a safety valve 226 to tank 222. The housing 224 is connected through a free duct 221 totank 222. Ducts 223 and 22'! extend through mutually rotatable'members 228 and 228 arrangedinthe center of the fifth wheel 22 of the tractor 28 andthesupport 28 resting thereon. I By means of a handle 83 a valve 238 can 'be opened or closed, thus controlling the quantity of fluid supplied by pressure ducts 223 which is allowed to be freely recycled and returned through duct 22! to tank 222. By closingvalve 238 to a greater or smaller extent more or less fluid is forced through a. spring loaded valve 23l into a passage 232 formed in the housing 224. The housing 228 is further connected by a duct 233 to both jacks and throughducts 234 and 235 to opposite ends of valve box 285.

Figs. 7 11 to 14 show four different positions which the control valve 88 may take within'th'e housing 224, which positions correspond with positions-N, A, B and C, respectively, of handle 81 as stated above.

pressure in passage 232 and jack 85 is allowed to-return to the tank 222. Consequently said jack 85 cannot be extended, even if valve 238 is fully closed and the entire quantity of oil supplied by pressure duct 223 is fed into passage 232.

If it is desired to push the container off the auxiliary frame, handle Si is placed in posi- 18) which is guided and slidably movable within the housing of said mechanism 58. Said cylinder 2.8 is movable along a stationary piston 282 connected with one end of said housing by a hollow piston rod 283 which comprises-a central tube 284.v The piston rod 288 is apertured near the piston 282 and the tube 284 extends through said piston. In this way difierent conduits communicate with the-space within the cylinder 28! at each side of the piston 282. These separate conduits are connected to separate ends of a valve box 285 comprising a movable valve member 286 which is urged to its central position by springs .28! and 288.

, while its upper run is connected to a sliding member 2l3 which-is guided through a longitudinal slotalong the top of said housing and to which member M3 the above mentioned rod 52 is connected; It will be clear that ,by admitting hydraulic pressure through one of the conduits in connecting rod 283 to one or the other side of piston 282, the piston 28! will move in one or the other direction. Since the lower run of chain piston 282.

tion A and valve 88 is thereby turned in the position schematically represented in Fig. 12. Oil or fluid pressure supplied through passage 2321s directed through the valve 88 to duct-238 to the transfer mechanism 58, displacing the valvemember 286 therein against spring 281. Thereby the passages within tube 283 and around tube 284 (which in the released central position of valve member 288 are both closed) are opened, so that pressure is admitted in the space of cylinder 28l at the right hand side of The cylinder 28! is thus forced to the right and so is the sliding member 213 with the connecting rod 52. Oil present in the left hand space of cylinder 28! is allowed to return to the tank 222 through tube 288, duct 235, a passage in valve member 88 (see Fig. 12) and return duct 221.

If on the other hand it is desired to pull the container upon the auxiliary frame, handle 81 is placed in the position B corresponding with the position of valve 88 shown in Fig. '13. Fluid pressure supplied through passage 232 is directed In the neutral position of said valve 88 shown in Figs. 10' and 11, any

sage in valve 08 (see Fig. 13) and return duct 221.

It is remarked that if neither of ducts 234 and 235 supply pressure to valve box 20-5 and the valve member 206 is in its central position, no fluid can pass through tube 204 or through the space around said tube 204 inside the connecting rod tube 203, so that cylinder MI is prevented from displacement in either direction, thus holding the container in its position (see Fig. 10 or 11).

In order to tilt the auxiliary frame after releasing trunnions 40 or 4| by means of lever 10,

handle 8| is placed in position C so that valve 88 is placed in the position of Fig. 14. Fluid pressure supplied through passage '232 is directed through duct 233 to the jacks '45- If it is desired to lower the auxiliary frame again, handle 8| is placed in the position N corresponding with the position of valve 88 shown in Figs. 10 and 11, so that pressure in jacks 45 is released through return duct 22?.

Referring now specifically to Fig. 8, there is shown in detail the universally adjustable hook 6| for holding the containers 3I and 32 in their vehicle carrying position on the auxiliary frame 1 30. The frame 30 may be provided with an upwardly extending bracket 38 carrying hollow sleeve or boss 90, through which sleeve extends a rod 62 threaded at one end at 63 and provided with a hook 64 at the other. threaded portion 63 is mounted an internally threaded sleeve, nut or hub I carrying a'hand wheel IOI, a flange I02, and a guiding extension I03. This extension I03 fits inside the sleeve 90 connected to the auxiliary frame 30, and together with the flange I02 provides a universal ball and socket type joint connection between the hook BI and the frame 30. This ball and socket type joint comprises two spherical surfaces I00 and I on sleeve I00, which have the same center of curvature I06, for radii I08 and I09 of said surfaces, respectively. These surfaces are re .spectively concave and convex engaging surfaces on the flange I02 and sleeve extension I03. Co-

operating with these surfaces are annular end.

of sleeve 90 having a convex spherical surface of radius I 08 against which the surface I 04 of flange I02 engages, and the internal cylindrical surface 9| of sleeve 90 having a radius I09 and against which the spherical surface I05 of sleeve extension I03 engages. The purpose of the extension I03 and its bearing surface I05 is to protect the threads 63 from being damaged by contact with the sleeve 90, when the hook rod 62 is in a limiting angular position. In order to maintain the sleeve I00 in engagement with the sleeve 90, there may be provided a spring I20 around the rod 62 which presses between washer I2I fixedly mounted to rod 62 and a loose washer I22 which engages the end of the sleeve 90 opposite from that engaged by the flange I02. The outer threaded end of the bar 62 may be provided with a fixed flange I25 to prevent the threaded sleeve I00 from being removed from the rod 62.

This adjustable hook mechanism 6I, thus permits the hook to be extended and retracted a suificient distance to engage its co-operating hook-eyes 65 (see Figs. 2, 3 and 4) mounted on containers 3I and 32, and then be tightened in these hook-eyes 05 to rigidly anchor the containers on to the auxiliary frame 30, as well as tighten the connection of opposing hooks 60 (see Figs. 1, 2, 6 and 7) in their co-operating hookeyes 66 near the other end of .the containers. The universal joint mounting for the hook 6| On the also provides for any discrepancy which may occur in the relative location of these hook-eyes on different containers.

Although the present invention has been specifically described in connection with a tractor and semi-trailer the same device may be applied to a full trailer or a complete truck with}- out departing from the scope of this invention. Furthermore, although a hydraulic mechanism has been shown for controlling the tilting and transferring mechanisms.. either one or both of these mechanisms may be operated by other types of power means employed on such vehicles.

While there is described above the principles of this invention is connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of this invention.

. Whatisclaimed is: V

1. In a vehicle for transporting a container said vehicle having a main frame, an auxiliary frame mounted on said main frame to carry said container, means to tilt said auxiliary frame forwardly and backwardly, and'means to move said containeronto and off of said auxiliary frame, the improvement .comprising means to lock said auxiliary frame in container carrying position and means cooperating with said looking means to prevent the operation of both said moving means and said tilting means when said auxiliary frame is in its container transporting position.

2. The vehicle of claim '1 wherein said locking means includes a firstmanually adjustable'control device having means for selectively locking the forward, the backward and both tilting mo"- tions of said auxiliary frame.

3. The vehicle of claim 2 wherein said locking means includes a second manually adjustable control device for selectively operating said tilting means and said moving means, and means for preventing the operation of said second device when said first manually adjustable control device locks both the tilting motions of said auxiliary frame.

4. The vehicle of claim 3 wherein said second manual device comprises means to control the amount of motion of said tilting means and said moving means.

5. In a vehicle for transporting a container, said vehicle having a main frame, an auxiliary frame mounted on said main frame to carry said container, a first hydraulic motor means to tilt said auxiliary frame forwardly and backwardly, a second hydraulic motor means to move said container onto and off of said auxiliary frame, the improvement comprising a first control means to selectively lock the forward, the backward and both tilting motions of said auxiliary frame, a second control means to selectively operate both said hydraulic motor means, and locking means to prevent the operation of said second control means when said auxiliary frame is in its container carrying position and said first control means locks both the tilting motions of said auxiliary frame.

6. The vehicle of claim 5 wherein said locking means comprises a lever cam, means to operate said lever cam by the motion of said first control means, and a cam engaging surface connected to said second control means which prevents the operation of said second control means when said cam is in engagement therewith.

'7. The vehicle of claim 5 wherein said second control means includes a hydraulic valve having four different positions corresponding respectively to inoperation, operation of said second hydraulic motor means in one direction, operation of said second hydraulic means in the other direction, and operation of said first hydraulic motor means.

8. The vehicle of claim wherein said first control means comprises pivoted hook means and lever means to operate said hook means to completely lock, partly lock and unlock the forward tilting motion and simultaneously and respectively to unlock, partially lock and completely lock the rearward tilting motion and wherein said locking means operates in the partially locked position of said hook means.

9. In a vehicle for transporting a container, said vehicle having a main frame, two parallel axle means fixedly mounted on said main frame, an auxiliary frame mounted on said main frame to carry said container, means to tilt said auxiliary frame alternately about either and neither of said axle means, and means to move said container onto and off of said auxiliary frame, the improvement comprising a control means to selectively lock said auxiliary frame to the forward, the backward, and both axle means on said main frame, and means to lock said moving means and said tilting means when said auxiliary frame is in its container transporting position and said control means locks said auxiliary frame to both said axle means.

10. The vehicle of claim 9 wherein said control means comprises separate hook means, a common link means connecting said hook means, and means to operate said common link means to completely engage, partly engage and disengage the forward axle means and simultaneously and respectively to disengage, partially engage, and completely engage the rearward axle means.

11. The vehicle of claim 10 wherein said common link means includes means to lock said moving means and said tilting means when said hooks are in their partial engagement positions with both of said axle means.

12. In a vehicle for transporting a container, said vehicle having a, main frame, an auxiliary frame tiltably mounted on said frame to carry said container, means to tilt said auxiliary frame forwardly and backwardly, and means to move said container onto and off of said auxiliary frame, the improvement comprising means to lock said auxiliary frame in container carrying position and means cooperating with said locking means to prevent the operation of both said moving means and said tilting means when said auxiliary frame is in its container transporting position, and additional means to fasten said container in position on said auxiliary frame.

13. The vehicle of claim 12 wherein said fastening means comprises a ball and socket type support for a longitudinally adjustable hook to engage said container, said support being mounted on said auxiliary frame.

14. The vehicle of claim 13 wherein said fastening means includes manually operated screw means to move said hook into and out of said ball and socket support for engagement and disengagement with said container, and for tightening the fastening of said container onto said auxiliary frame.

15. A fastening means comprising a cylindrical support, a threaded rod extending through said support, a hook on said rod, means to thread said rod through said support to extend and retract said hook, and ball and socket joint means between said threading means and said support to permit angular movement of said rod with respect to the axis of cylindrical support, said ball and socket means comprising two separate spherical engaging surfaces of different radii and the same center of curvature, located between said threading means and said support.

16. The fastening means of claim 14 wherein said ball and socket means comprises two separate spherical engaging surfaces of different radii and the same center of curvature, located between said threading means and said support.

HUBERTUS JOSEPHUS VAN DOORNE.

REFERENCES CITED The following references are of record inthe file of this patent:

UNITED STATES PA I n." N TS Number Name Date 1,821,327 Scott Sept. 1, 1931 1,883,538 Bywater Oct. 18, 1932 1,910,398 Ludington May 23, 1933 2,114,157 Towson Apr. 12, 1938 2,132,612 Faries Oct. 11, 1938 2,251,293 Schwartz et a1 Aug. 5,1941 2,282,352 Fitch May 12, 1942 FOREIGN PATENTS Number Country Date 334,632 Great Britain Sept. 11, 1930 332,910 Italy Dec. 11, 1935 50,510 Holland May 16,1941 

